Gleb Natapov wrote on 2013-03-22:
> On Fri, Mar 22, 2013 at 08:05:27AM +0000, Zhang, Yang Z wrote:
>> Gleb Natapov wrote on 2013-03-22:
>>> On Fri, Mar 22, 2013 at 01:24:05PM +0800, Yang Zhang wrote:
>>>> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>>>>
>>>> Current interrupt coalescing logci which only used by RTC has conflict
>>>> with Posted Interrupt.
>>>> This patch introduces a new mechinism to use eoi to track interrupt:
>>>> When delivering an interrupt to vcpu, the pending_eoi set to number of
>>>> vcpu that received the interrupt. And decrease it when each vcpu writing
>>>> eoi. No subsequent RTC interrupt can deliver to vcpu until all vcpus
>>>> write eoi.
>>>>
>>>> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>>>> ---
>>>> virt/kvm/ioapic.c | 40 +++++++++++++++++++++++++++++++++++++++- 1
>>>> files changed, 39 insertions(+), 1 deletions(-)
>>>> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
>>>> index c991e58..df16daf 100644
>>>> --- a/virt/kvm/ioapic.c
>>>> +++ b/virt/kvm/ioapic.c
>>>> @@ -114,6 +114,29 @@ static void rtc_irq_restore(struct kvm_ioapic
> *ioapic)
>>>> ioapic->rtc_status.pending_eoi = pending_eoi;
>>>> }
>>>> +static void rtc_irq_ack_eoi(struct kvm_vcpu *vcpu,
>>>> + struct rtc_status *rtc_status, int irq)
>>>> +{
>>>> + if (irq != RTC_GSI)
>>>> + return;
>>>> +
>>>> + if (test_and_clear_bit(vcpu->vcpu_id, rtc_status->dest_map))
>>>> + --rtc_status->pending_eoi;
>>>> +
>>>> + WARN_ON(rtc_status->pending_eoi < 0);
>>>> +}
>>>> +
>>>> +static bool rtc_irq_check(struct kvm_ioapic *ioapic, int irq)
>>>> +{
>>>> + if (irq != RTC_GSI)
>>>> + return false;
>>>> +
>>>> + if (ioapic->rtc_status.pending_eoi > 0)
>>>> + return true; /* coalesced */
>>>> +
>>>> + return false;
>>>> +}
>>>> +
>>>> static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
>>>> {
>>>> union kvm_ioapic_redirect_entry *pent;
>>>> @@ -229,6 +252,7 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int
>>> irq)
>>>> {
>>>> union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
>>>> struct kvm_lapic_irq irqe;
>>>> + int ret;
>>>>
>>>> ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
>>>> "vector=%x trig_mode=%x\n",
>>>> @@ -244,7 +268,14 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic,
> int
>>> irq)
>>>> irqe.level = 1;
>>>> irqe.shorthand = 0;
>>>> - return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
>>>> + if (irq == RTC_GSI) {
>>>> + ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
>>>> + ioapic->rtc_status.dest_map);
>>>> + ioapic->rtc_status.pending_eoi = ret;
>>> We should track status only if IRQ_STATUS ioctl was used to inject an
>>> interrupt.
>> We already know RTC will use IRQ_STATUS ioctl. Why check it again?
>>
> QEMU does. QEMU is not the only userspace.
And this will break other userspace.
Best regards,
Yang
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
